Generally speaking changes in ribbon forces will dramatically affect the print registration ability of any thermal transfer printer. This is easily observed especially when the ribbon diameter changes from a fresh ribbon roll to an empty roll. Having the ability to control the ribbon tension dynamically as the diameter of ribbon changes greatly improves the print registration capability.
There are printers with the ability to control the ribbon tension dynamically. Usually this is accomplished by using an individual DC motor on each of the ribbon rewind and ribbon supply spindles with a two-encoder feedback system. Print precision on these performance class printers is excellent. However, having two motors affects final product cost and system complication.
Therefore, a need exists for a printer where the ribbon tension can be controlled using a single motor.